Sulfuric Acid's Industrial and Practical Uses

Steps:

• Evaluate option A: Check catalyst in Contact process for sulfuric acid production.
• Evaluate option B: Confirm sulfuric acid's role in common battery types.
• Evaluate option C: Assess if sulfuric acid acts directly as a fertilizer.
• Evaluate option D: Verify if sulfuric acid serves as a food preservative.

Why B is correct:

• Sulfuric acid (H₂SO₄) is the electrolyte in lead-acid batteries, enabling the electrochemical reaction that produces electrical energy via Pb + SO₄²⁻ → PbSO₄ + 2e⁻.

Why the others are wrong:

• A: Vanadium pentoxide (V₂O₅), not iron, catalyzes the oxidation of SO₂ to SO₃ in the Contact process.
• C: Sulfuric acid produces fertilizers like ammonium sulfate but is not used as one itself due to its corrosiveness.
• D: Food preservatives include benzoic acid or sulfites, not concentrated sulfuric acid, which is hazardous for consumption.

Final answer: B